Wimberley C-12 Quick-Release Clamp The C-12s screw knob clamp accepts a wide variety of plate widths and features Wimberley safety stop technology The geometry of the mounting holes allow you to securely attach the clamp to retrofit a variety of ball heads For Compatibility Please see: http://tripodhead.com/products/C12-compatibility.cfm Anodized 6061 Aluminum, Stainless Steel fasteners Made in USA. Assembled in Charlottesville, Virginia